1. Field of the Invention
2. Description Related to the Prior Art
A known type or photo film has a magnetic recording layer, which consists of a coating applied to a surface reverse to photographic emulsion, and to which information is magnetically recordable. Predetermined photo film information is recorded to the magnetic recording layer, and includes frame numbers, photo film sensitivity, the number of available frames, product name and the like. In taking an exposure, those kinds of information are read and used for conditioning the exposure. Also information of a particular condition determined for each exposure is recorded to the magnetic recording layer.
A camera for use with the photo film having the magnetic recording layer is provided with a magnetic head for the purpose of magnetic recording and reading. The magnetic head is fixedly secured to a photo film support plate, which supports a back surface of the photo film positioned in an exposing station, and keeps the photo film flat. For the magnetic recording and reading with the magnetic recording layer in an exact manner, it is essential to stabilize pressure in contact of the magnetic head with the magnetic recording layer.
FIG. 18 is now referred to, and the magnetic head and its relevant structure in the camera are described. The camera has an exposure aperture which defines a region to be exposed on photo film 211. There is a photo film support plate 213 or pressure plate disposed behind the exposure aperture. The photo film support plate 213 supports the photo film 211 in contact with a back surface of the photo film 211 positioned on the exposure aperture, to keep an imaging frame flat. A magnetic recording layer is formed by applying a coating of magnetic material to the back surface of the photo film 211, which is opposed to the photo film support plate 213. A magnetic head 215 is secured to the photo film support plate 213, and contacts the magnetic recording layer of the photo film 211 to record information to and/or read information from a magnetic recording area.
In FIG. 18, the magnetic head 215 is positioned to protrude forward from a head base plate 216. The photo film support plate 213 has an opening 217 through which the magnetic head 215 is disposed. The head base plate 216 is kept so positioned that the magnetic head 215 projects from the opening 217 at a predetermined projecting amount A experimentally obtained for the magnetic head 215 to give suitable pressure to the magnetic recording layer of the photo film 211. When the head base plate 216 is positioned, adhesive agent 218 is applied to the head base plate 216 and the photo film support plate 213 to extend from the rear face of the head base plate 216 to the rear face of the photo film support plate 213. The adhesive agent 218 is hardened and forms an adhesive layer in a certain spread area, to secure the head base plate 216 fixedly to the photo film support plate 213. There are plural positions on the periphery of the head base plate 216 where the adhesive agent 218 is applied.
To pour the adhesive agent 218, the head base plate 216 and the photo film support plate 213 are kept positioned with their rear directed upwards. The adhesive agent 218 is applied to overlapped portions between the head base plate 216 and the photo film support plate 213. An example of the adhesive agent 218 is an ultraviolet cure type which has a characteristic which is ordinarily fluid and hardened in response to application of ultraviolet rays.
There is a problem in the method of pouring the adhesive agent 218 on the rear faces of the photo film support plate 213 and the head base plate 216, in that the adhesive agent 218 flows to change an area where the adhesive agent 218 spreads. As the head base plate 216 itself has a relatively small area of the surface, the adhesive agent 218 comes to have an appearance giving a poor impression, because plural layers of the adhesive agent 218 overlap on one another when the adhesive agent 218 is spread on the rear of the head base plate 216. Furthermore, the spread area of the adhesive agent 218 is likely to be larger than is sufficient. The used amount of the adhesive agent 218 is wastefully large. An amount of the adhesive agent 218 to be poured for one time may be predetermined to avoid the excessive use of the adhesive agent 218. However another problem occurs in that the adhesive agent 218 is poured in an unacceptable position offset to the photo film support plate 213. A spread area defined by the adhesive agent 218 on the head base plate 216 may become extremely small, to lower the strength of fixing the head base plate 216 to the photo film support plate 213.
In view of the foregoing problems, an object of the present invention is to provide a photo film support device and a magnetic head securing method for the same in which a magnetic head can be reliably secured to the photo film support device with great ease.
Another object of the present invention is to provide a photo film support device and a magnetic head securing method for the same in which adhesive agent is prevented from overflowing rearwards from a head base plate.
An additional object of the present invention is to provide a photo film support device and a magnetic head securing method for the same in which an assembly machine for those can be simply constructed without extremely difficult adjustment.
Still another object of the present invention is to provide a photo film support device which consists of a plate of metal and which can be produced with great efficiency.
In order to achieve the above and other objects and advantages of this invention, a photo film support device is incorporated in a camera, for supporting a back of photo film, the photo film having a magnetic recording area. The photo film support device includes a photo film support plate. An opening is formed in the photo film support plate. A magnetic head is disposed to project forwards from inside the opening, for recording information to and/or reading information from the magnetic recording area. A head base plate is mounted on a rear face of the photo film support plate to cover the opening, for supporting the magnetic head. Adhesive agent is applied to at least one portion of the periphery of the head base plate, and hardened for securing the head base plate to the photo film support plate. At least one recess or at least one projection is disposed on a periphery of the head base plate and/or on a rear face of the head base plate in a vicinity of the periphery, the adhesive agent being disposed to extend from a front face of the head base plate to a surface of the recess or the projection, the recess or the projection enlarging a contact area between the adhesive agent and the head base plate.
In a preferred embodiment, the at least one portion of the periphery of the head base plate includes first and second edges opposite to each other, and the at least one recess or the at least one projection is located on the first and second edges.
The at least one recess is first and second recesses, formed in the head base plate by cutting a rear end of the first and second edges.
The head base plate further has first and second projection trains, respectively including plural projections, disposed on an inside of the first and second recesses to project toward the periphery.
In another preferred embodiment, the at least one projection is first and second projection trains, respectively including plural projections, disposed on the first and second edges to project from the head base plate in a peripheral direction.
By this construction, the magnetic head can be reliably secured to the photo film support device with great ease, because of the contact area enlarged by the recess or the projection between the adhesive agent and the head base plate.
According to another aspect of the present invention, adhesive agent is applied to at least one adhesion section disposed on a periphery of the head base plate, and hardened for securing the head base plate to the photo film support plate. An anti-overflow structure is disposed to project rearwards from the photo film support plate, positioned outside the at least one adhesion section, for blocking the adhesive agent, to prevent the adhesive agent from overflowing about the head base plate.
In a preferred embodiment, the anti-overflow structure includes an anti-overflow plate. A first cutout is formed in the anti-overflow plate, substantially rectangular, and disposed about the head base plate.
Furthermore, a double-sided adhesive sheet attaches the anti-overflow plate to the photo film support plate. A second cutout is formed in the double-sided adhesive sheet, substantially rectangular, and overlaid on the first cutout.
By this construction, the adhesive agent is prevented from overflowing rearwards from the head base plate, as the anti-overflow structure projects rearwards for blocking the adhesive agent.
According to an additional aspect of the present invention, at least first and second head support projections are disposed in at least first and second positions defined in the opening opposite to each other, the first and second head support projections projecting from the opening rearwards by a predetermined height. A head base plate is mounted on a rear face of the photo film support plate, contacted by the first and second head support projections to cover the opening, for supporting the magnetic head. At least one spacer is mounted between the photo film support plate and the photo film support plate and outside the first and second head support projections before the head base plate is mounted on the photo film support plate, the spacer having a predetermined thickness smaller than the predetermined height. Adhesive agent is poured and hardened between the head base plate and the spacer.
In a preferred embodiment, the photo film support plate is a metal plate, initially first and second projecting portions are formed in the first and second positions of the opening, then the first and second projecting portions are bent rearwards, the first and second projecting portions having a predetermined initial height as measured in a rearward direction, and the predetermined initial height being greater than the predetermined height, and then the first and second projecting portions are depressed in a forward direction to form the first and second head support projections at the predetermined height.
By this construction, an assembly machine for those can be simply constructed without extremely difficult adjustment, as the head base plate contacted by the first and second head support projections, and can be precisely positioned on the photo film support plate readily without difficulties.
According to still another aspect of the present invention, a photo film support plate of metal is produced by press. At least two metal pins of a cylindrical shape is formed integrally with the photo film support plate to project forwards therefrom, the metal pins being produced in producing the photo film support plate by subjecting a top end and a bottom end of the photo film support plate to drawing press, and the metal pins regulating respective longitudinally extending edges of the photo film therebetween.
Furthermore, circular recesses are formed behind the metal pins simultaneously therewith by the drawing press deforming the top end and the bottom end of the photo film support plate. The metal pins have a diameter substantially equal to a thickness of the photo film support plate.
By this construction, a photo film support device can be produced with great efficiency, because the metal pins can be produced with the photo film support plate only at one time.